I know trades are a touchy subject in most worlds, and this could just create more problems. However, when trying to work around salaries and throwing in minor league players (such that they do in the MLB) it would make things a lot easier if trades could involve more than 3 players. Make 4 or 5 players per team an option. Even if it just a custom rule that worlds can set up I think it would enhance how trades can be built.